For a lot of investors, this might be the alarm bell to start investing in cannabis, but Cramer says that investors have missed their chances if they're not already in companies such as Tilray (TLRY) , Canopy Growth (CGC) , or Green Organic Dutchman (TGOWF) .

The reason behind Cramer's advice is due to the fact that both Canopy and Tilray skyrocketed yesterday. Both stocks were up double-digits by the time that trading closed for the day.